[gmx-users] using nopbc is not equal to using pbc with big box dimensions

[Dr. Vitaly Chaban]

The fact that images are separated by a distance exceeding the cutoff,
does not mean that they do not interact electrostatically.

I hope the results are not much different...


Dr. Vitaly V. Chaban


>
> On Mon, Dec 2, 2013 at 11:46 PM, Golshan Hejazi <golshan.hejazi at yahoo.com>wrote:
>
>> Hello,
>>
>> I would like to compute the energy of a system in vacuum. For this I first
>> computed energy by using nopbc and putting rculomb=rvdw=0 ...
>> Then I computed the energy using pbc with a big box dimension (periodic
>> images are separated by a length more than cutoff )... this means that
>> periodic images dont interact ... results are different ... but which one
>> is correct?
>>
>>
>> Can you help me to understand this better
>> G.